What are the special effects for each damage type, and when do they trigger?

I've noticed that when I use a weapon with cold damage, every attack "snares" my targets, even when I don't use any skill or item which explicitly snares or slows. I'm guessing this is due to the cold damage.

• Do other damage types have a special effect this way? If they do, what are those effects?
• Does it also happen if I get a bonus damage from a source which is not directly on the weapon? e.g. if I have a ring which adds cold damage, will all my attacks snare?
• Do these special effects always trigger on attack, or only under certain conditions?

Unlike in Diablo II, on-hit elemental damage is simply that - bonus damage, with the sole exception of cold damage (which has a small snare). Frost damage does a little less damage comparatively because of this.

While there was originally a more complex critical hit system (as documented below), that functionality did not make it to the final game.

Critical hits just add damage.

Historical Answer:

More interestingly, in the Diablo III Beta, each type of damage has a different effect on a critical.

• Physical: Double Damage

• Arcane: Silences targets for 4 seconds (prevents abilities)

• Cold: Freezes targets for 2 seconds (Duration can be affected by talents, etc.)

• Fire: Sets them on fire, fire DoT (tick rate scales off weapon speed)

• Lightning: Stuns targets for 2 seconds (Duration can be affected by talents, etc.)

Poison and Holy presumably have effects on a critical hit also, but I haven't been able to find info on them.